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Clutch fork shortcomings

Posted: 18 Oct 2013 00:08
by Cobber
<font size="2"><font face="Comic Sans MS">I been thinking about the shortcomings of the design of the clutch fork and ball pivot, fitted to our cars.
It really is a crap piece of design.

Perhaps the ball pivot arrangement could be replaced with a bearing mount that a new design of fork could pivot on, something a bit like a roller rocker pedestal.
It could use sealed bearings or bushing.

The fork arm would have a proper method of retaining the clutch slave cylinder push rod, instead of the stupid set up we have now that can allow the push rod to fall off whist replacing the slave cyl, necessitating the removal of the gearbox for the rods reinstatement!

The fork arm and pedestal would need to be cast, forged or machined from a billet instead of the awful bit of pressed tinware we have now.

I realise that this wouldn't be commercially viable these days, but the engineer in me just keeps on wanting to eliminate bad design.</font id="Comic Sans MS"></font id="size2">


"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.
76' Ford F100

Posted: 18 Oct 2013 03:26
by Troy ODoherty
It would be easier to use a modern slave system that lives in the bellhousing. This is what I use in the rally car. Very reliable. No need for pivots or release forks.[:D]

Cheers Troy

Posted: 18 Oct 2013 05:19
by john 215
Hi.

With my learned friend Troy, would be the best way to over come this problem. I know the Ford T5 gearbox runs this set up, would req an adaptor turned up to fit a LT 77 box though. If you are handy on a lathe would be possible.

Cheers John



ImageImageImage Image
LIVE LIFE A QUARTER OF A MILE AT A TIME!

1976 Speke FHC Beauty

1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6, BUILT NOT BROUGHT !!!!

Posted: 18 Oct 2013 06:44
by Cobber
<font size="2"><font face="Comic Sans MS">The thing I don't like about annular type clutch slave cylinders is they are a bugger to replace! </font id="Comic Sans MS"></font id="size2">



"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.
76' Ford F100

Posted: 18 Oct 2013 11:55
by parrish
Conversion to a bearing mount is possibly a litte OTT.
I have had my share of problems with this little area of BL design and may i suggest you just wire the lever onto the ball joint.
In the unlikely event! of you needing to remove the slave cylinder the wire should retain the lever in position.
However Cobber should you come up with a marketable solution with a bearing mount Ill have one!
Steve

1983 Del lines TR8. FIAT 131 Abarth Replica.1977 FIAT 131 1600 TC, 1996 BMW Z3,. 2009 Sport Ka, 2012 Ford Fusion.

Posted: 18 Oct 2013 11:56
by Workshop Help
Cobber, be thankful out TR7's don't have the miserable nylon pivot pin used in BMW's.

Granted, the Triumph design is a lot on the technological stone-ax, Neanderthal side, mine lasted from 1976 to 2007 and 121,000 miles. That's a pretty decent service life for an item subject to constant mechanical stress. I'll also grant you replacing it was a three ring circus, tho it did prompt the LT77 gearbox conversion which was the best thing this car has ever had.

So, rather than reinventing the wheel here, 'when', rather than 'if', the pivot pin does pierce the clutch fork dimple, I respectfully suggest going back with whats there, except for cramming as much high temperature grease as possible into the divot on the end of the pivot pin and in the clutch fork dimple. And, make sure there are no ragged edges.

Mildred Hargis

Posted: 18 Oct 2013 20:45
by kstrutt1
You used to able to get uprated ones, most just had a bar welded across the back of the pivot (front when installed) that said mine has done around 200,000 mikes now with no sign of failure.